<template>
  <div id="root">
    <div class="todo-container">
      <div class="todo-wrap">
        <MyHeader @addToDo="addToDo"/>
        <MyList :todos="todos"/>
        <MyFooter
        :todos="todos" @checkAllToDo="checkAllToDo"
        @clearAllToDo="clearAllToDo"
        />
      </div>
    </div>
  </div>
</template>

<script>
import pubsub from "pubsub-js"
import MyHeader from './components/MyHeader';
import MyList from './components/MyList';
import MyFooter from './components/MyFooter';

export default {
  name: 'App',
  components: {
    MyHeader,
    MyList,
    MyFooter
  },
  data(){
    return {
        todos: JSON.parse(localStorage.getItem('todos')) || []
    }
  },
  watch: {
    todos: {
      deep: true,
      handler(value){
        localStorage.setItem('todos', JSON.stringify(value));
      }
    }
  },
  methods: {
    //添加一条todo
    addToDo(todoObj){
      this.todos.unshift(todoObj);
    },
    //勾选一条todo
    checkToDo(id){
      this.todos.forEach(todo => {
        if(todo.id === id) todo.done = !todo.done;
      });
    },
    //删除一条todo
    deleteToDo(_, id){
      this.todos = this.todos.filter(todo => todo.id !== id);
    },
    //更新一条todo
    updateToDo(title, id){
      this.todos.forEach(todo => {
        if(todo.id === id) todo.title = title;
      });
    },
    //全选todo
    checkAllToDo(done){
      this.todos.forEach(todo => {
        todo.done = done;
      })
    },
    //清除所有已完成任务
    clearAllToDo(){
      this.todos = this.todos.filter(todo => !todo.done);
    }
  },
  mounted() {
    this.$bus.$on("checkToDo", this.checkToDo);
    // this.$bus.$on("deleteToDo", this.deleteToDo);
    //use pubsub way to achieve above function
    this.pid = pubsub.subscribe("deleteToDo", this.deleteToDo);
    this.$bus.$on("updateToDo", this.updateToDo);
  },
  beforeDestroy() {
    this.$bus.$off(["checkToDo", "updateToDo"]);
    pubsub.unsubscribe(this.pid);
  }
}
</script>

<style>
/*base*/
body {
  background: #fff;
}

.btn {
  display: inline-block;
  padding: 4px 12px;
  margin-bottom: 0;
  font-size: 14px;
  line-height: 20px;
  text-align: center;
  vertical-align: middle;
  cursor: pointer;
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.2), 0 1px 2px rgba(0, 0, 0, 0.05);
  border-radius: 4px;
}

.btn-danger {
  color: #fff;
  background-color: #da4f49;
  border: 1px solid #bd362f;
}

.btn-edit {
  color: #fff;
  background-color: #49dab3;
  border: 1px solid #33967c;
  margin-right: 10px;
}

.btn-edit:hover {
  color: #fff;
  background-color: #33967c;
}

.btn-danger:hover {
  color: #fff;
  background-color: #bd362f;
}

.btn:focus {
  outline: none;
}

.todo-container {
  width: 600px;
  margin: 0 auto;
}
.todo-container .todo-wrap {
  padding: 10px;
  border: 1px solid #ddd;
  border-radius: 5px;
}
</style>
